Head for lifting-jacks.



F. l. JOYCE. HEAD FOR LIFTING JACKS.

APPLICATION FILED APR. 14, 1914.

1,137,41 Patented Apr. 27, 1915.

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FRANK I. JOYCE, OF DAYTON, OHIO.

HEAD FOR LIFTING-JACKS.

Specification of Letters Patent.

Original application filed January 27, 1912, SerialNo. 673,901. Divided and this application filed April 14,

1914. Serial No. 831,761.

To all whom it may concern Be it known that I, FRANK I. JoYon, a citizen of the United States, and a resident of the city of Dayton, in the county of Montgomery and State of Ohio, have invented certain new and useful Improvements in Heads for Lifting-Jacks, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

This is a divisional application of my application filed January 27, 1912, for improvements in lifting jacks, Serial No. 673,901. The features of the jack head which form the subject matter of this application have relation particularly to the reduction to a minimum of the friction between the screw and the load of a screw jack, by introducing a hydraulic support for the load. Generally the hydraulic support for the load is applicable to any jack, as will be obvious as hereinafter developed.

The several features of the invention herein and the various advantages resulting from their use conjointly or otherwise will be apparent from the following description and claims.

In the drawings, the figure is a side elevation of my improved jack showing the head in central vertical section.

The ack to which I have applied my improved head, and to which form of jack the new head is especially valuable, is a screw jack, having a standard 1, screw 2, nut 3 in the standard screwthreaded to receive the screw, beveled gear 4: on the screw and beveled gear 5 in mesh with the first gear. The beveled gear 5 is carried on a shaft 6, with a crank 7 on the end journaled in a bearing 8 bolted to the housing 9. This housing is slidably mounted on the standard and is raised when the screw is turned by means of the crank 7 and the gears.

On the beveled gear 4 of the screw of the jack is a bored, upwardly extending hub 23 which has a bearing and revolves in the bearing surface 24-. of the cap 25, which cap is screwed into the upper end of the housing 9, which completes the housing for the jack.

Seated in the cylindrical bore 26 in the hub 23 is the ram 27. This ram extends above the cap 25 to take the load, and at its lower end is provided with the hydraulic cup packing 28 held in place by the packing ring 29 and packin nut 30, and also with a lock screw 31 to o'set the tendency to un- The ram 27 is cored out to form a reservoir 32 which opens into the cylindrical space 26 in the hub 23 of the crown gear through the passage 33 normally closed by the spring-pressed valve 3 1. The reservoir 32 is closed by the screw plug 35, provided with the air vent 36, normally closed by the downwardly opening spring-pressed valve 37, in order to allow air to be drawn into the reservoir as the oil therein is drawn out, but to prevent the oil from escaping as the jack is thrown around. The ram is also supported by a conical spring 38 seated between the base of the ram and the bottom of the reservoir 26. A conical bearing 39 is also provided to engage the conical seat &0 in emergencies when the oil has been allowed to run out of the reservoir. A roller bearing 41 is also provided interposed between the upper surface of the hub 23 and the plate 12 underneath the cap 25 for the purpose of holding the gearing in proper mesh and to take thedload when the ground lift 43 is being use The cylindrical space 26 and the reservoir 32 are filled with oil, so that the ram 27 will be supported by the oil in the space 26, and the pressure when the ram carries the load will be borne by the oil, while the hub 23 will be free to rotate with the gearing. There will be some slight leakage while the cup packing is expanding to take the load, and the ram will therefore settle slightly. When the jack is relieved from the load, the coiled spring 33 will raise the ram to its proper adjustment, and the partial vacuum thus produced will force the oil from the reservoir 32 into the cylindrical space 26, to replace what has passed the packing, While taking the load, while the air vent 36 will open to relieve the vacuum in the reservoir In this way, it will be evident that a very perfect antifriction thrust bearing is provided for the screw when subjected to the load.

It is evident that this head could be used in a lever jack where there is no housing such as the housing 9 and 25, to be raised and lowered. No illustration of this has been deemed necessary because, if the top portion 25 and the rollers 41 were to be removedin the figure, the head thus formed would then be in shape'to be-used on a lever" ack. v

The reason for selecting the screw jack for illustration of the use ofthe improved jack head is because the functions of the head in relieving parts from strain are most useful v for this kind of jack.

--ram to form an anti-friction thrust bearing for the raising means, with an oil reservoir 1n the ram, and a passageway therefor for the socket to maintain the liquid supply and a valve normally to close the passageway adapted to open to permit passage of oil upon release of the load. 7

2. In a lifting jack, a standard and a lifting screw mounted therein, a ram to engage the load with a socket'in the head of the adapted to open to permit the socket to maintain the liquid supply and a valve normally to close the passageway passage of oil upon release of the load.

3. In a lifting jack, a standard and a lifting screw mounted therein, a ram to engage the load with a socket in the head of the v screw within which the ram is seated, and a liquid cushion in the'socket for the base of the ram to form'an anti-friction thrust bearing for the screw, with an oil reservoir in the'ram, and a passageway therefor to the socket to maintain the liquid supply and a valve normally to close the passageway, a spring bearing between the base i of the socket and the bottom of the ram to return the ram to normal position upon leakage of the liquid from the-socket and to permit the liquid supply valve to open to renew the liquid in the socket." I

' FRANK I. JoYoE.

'Attest: I

Gno; WV. LLEWELLYN, v

RUTH RoHRnn.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. G. 

